I like this, but would really like a convert-to-base-units function.

  ≫ sqrt(1/(eps0 mu0)) ->m/s
    sqrt(1 / (eps0 × mu0)) -> m / s
     = 299833000 m/s
  ≫ sqrt(mu0/eps0) ->ohm
    sqrt(mu0 / eps0) -> Ω
     = 377.031 Ω